air defense identification zone which includes the air space over the islands saying foreign airlines must now warn china of their flight plans before entering air space many the east china sea. now, remember, the china/japan rivalry goes back, oh, a thousand years? the japanese see this as a sign of chinese aggression and are furious. this morning in a news conference with japan's prime minister, vice president biden warned that beijing risks a potentially dangerous confrontation with japan and its allies, which, of course, means us. >> we, the united states, are deeply concerned by the attempt to unilaterally change the status quo in the east china sea. this action has raised regional tensions and increased the risk of accidents and miscalculation. >> anonymously, white house advisers have been more candid. one adviser told -- one adviser to president obama told "the new york times," "it's pretty clear this isn't really about the islands. it's about a desire of some in china to assert themselves that-in ways that until recently they didn't have the military capability to make real.